The present invention relates to a cap for closing the mouth of a vehicle fuel tank filler neck, and particularly to a tank filler neck closure cap designed to withstand the application of excessive closure torque and to reset automatically to an installation configuration upon removal from the filler neck. More particularly, the present invention relates to a quick-on filler neck closure cap having a torque-control mechanism that is operative during cap installation and a spring-driven closure member reset mechanism that is operative during cap removal.
Conventional caps for closing the filler neck of a vehicle fuel tank typically include a closure member carrying a seal for closing and sealing the mouth of the filler neck and a handle for turning the closure member to mount the closure member and seal in the filler neck. A typical filler neck cap includes a ring-shaped seal made of a resilient gasket material that is compressed between the cap and a filler neck receiving the cap to establish a sealed connection between the cap and the filler neck when the cap is mounted on the filler neck.
Frequent over-tightening of a filler neck fuel cap can crush or otherwise damage the O-ring gasket which provides the seal between the cap and the filler neck. The torque-control mechanism was developed to limit the amount of torque which could be applied by a user in the cap-advancing direction as the user rotates the cap on the filler neck to its fully seated filler neck-closing position thereon. Thus, a torque-control mechanism helps minimize wear and tear on the O-ring gasket and preserves the sealing capability of the gasket. See, for example, U.S. Pat. Nos. 4,913,303 to Harris and 5,110,003 to MacWilliams, the disclosures of which are incorporated by reference herein.
More and more vehicle drivers are using the self-service bays at gasoline stations and filling their own fuel tanks. Some people have found that it is difficult to remove and install a conventional filler neck cap during refueling. A quick-on cap that is readily installable on and removable from a filler neck by a user without a lot of effort and that is configured to establish a sturdy sealed connection between the cap and the filler neck consistently during use would be welcomed by users of such caps.
Many quick-on filler neck caps are configured to be engaged with internal flanges formed in the filler neck to cause the cap to be retained quickly and easily in the filler neck after being rotated, for example, one-eighth or one-quarter of a turn in the filler neck. Quick-on caps are disclosed, for example, in U.S. Pat. Nos. 5,395,004 to Griffin and Harris; 5,381,919 to Griffin and Harris; 5,480,055 to Harris and Griffin; and 5,794,806 to Griffin and Harris; and in U.S. application Ser. No. 09/254,516 to Griffin, filed on Mar. 9, 1999, the disclosures of which are incorporated by reference herein.
According to the present invention, a filler neck cap includes a closure member adapted to close a filler neck, a handle, and a torque-transmission ring positioned to lie between the handle and the closure member and coupled to the handle to rotate therewith. A connector is positioned to lie between the torque-transmission ring and the closure member. The connector is configured to provide a torque-limited connection between the ring and the closure member during rotation of the handle and the ring in a cap-advancing direction and to provide a direct-drive connection between the ring and the closure member during rotation of the handle and the ring in a cap-removal direction.
An axial spring is provided to yieldably urge the torque-transmission ring in a direction toward the closure member during rotation of the handle and the ring about an axis with and relative to the closure member to maintain the torque-limited connection. The axial spring is positioned to extend between the torque-transmission ring and the handle.
In preferred embodiments, the axial spring includes several spring arms and each spring arm includes a fixed end coupled to an annular inner edge of the torque-transmission ring and a free end arranged to engage and ride on a foundation wall provided on the underside of the handle and arranged to face downwardly toward the underlying torque-transmission ring. The spring arms are made of a spring material and act to "push" the torque-transmission ring downwardly toward the closure member to maintain the torque-limited connection during cap installation in a filler neck whether the handle and torque-transmission ring are cooperating to turn the closure member in the filler neck to assume an installed position therein or whether the handle and torque-transmission ring are rotating together as a unit relative to the closure member after the closure member has been installed in the filler neck during a torque-override condition wherein drive teeth on the ring ramp on and over underlying driven teeth on the closure member to create the familiar "clicking" sound vehicle refuelers associate with the torque-override function of a vehicle fuel cap.
A rotary spring is coupled to the handle and to the torque-transmission ring and arranged to cause the closure member to rotate relative to the handle automatically upon removal of the cap from the filler neck prior to refueling. The cap is configured to provide a lost-motion driving connection during cap removal so that the handle always rotates through a lost-motion angle during initial rotation of the handle about an axis relative to the filler neck in a cap-removal direction. Upon removal of the cap from a filler neck, while the user is still gripping the cap by holding onto the handle, the rotary spring inside the cap functions to rotate the torque-transmission ring and the closure member, which is coupled to the torque-transmission ring by a direct-drive connection established during cap removal, relative to the handle to cause the closure member to be rotated to a predetermined position so that the user can later positively and quickly reinstall the quick-on cap in the filler neck without experiencing any "lost motion" movement between the handle and the closure member.
In preferred embodiments, the rotary spring is a helical clock spring arranged to lie adjacent to an annular outer side wall of the handle. One end of the spring is coupled to a downwardly projecting post appended to an underside of the handle and the other end of the spring is coupled to an upwardly projecting post appended to a top surface of the torque-transmission ring. The helical clock spring is arranged to lie in a radially outward position against the annular side wall of the handle and away from the central axis of rotation to allow an open space to exist in the cup under a center portion of the handle.
In preferred embodiments, the filler neck cap further includes a conductor configured to conduct an electrical charge from the handle to the filler neck during rotation of the handle relative to the closure member and before movement of the closure member to break a seal established between the closure member and the filler neck. The conductor includes an annular band coupled to the torque-transmission ring to rotate therewith and a finger appended to the annular band. The finger is arranged to be moved by a boss on the handle to establish electrical contact between a tip of the finger and the filler neck before the closure member is moved to open the filler neck.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.